Shipping calculated at Checkout. Finnish sauna heater rocks are great for wood burning sauna stoves or electric sauna heaters. Proper sauna rock size is important for electric heater airflow. Igneous sauna rocks are proper density to evenly hold and release heat as well as provide a large surface area to generate steam. These sauna rocks can be used in most brands of electric, gas or wood burning sauna heaters. Proper size and type of rocks should be used to comply with heater warranty and avoid electric element damage. This amount of rocks is also great for heater brands that do not include rocks.